Distinguish a source from material to apply

A citation such as “this distinction follows X” tells you where a claim or explanation comes from. Use the material already given when it is sufficient; opening its source is not an automatic extra step. Inspect the source when its meaning, assumptions or evidence matter to a question about relying on it.

An instruction such as “use X to compare these arrangements” asks for a contribution to the present work. Follow its conditions and distinguish a required move from one suggested way. Reuse an adequate result or an already understood Method when it fits; otherwise obtain and use the supplying explanation, then bring the result back to the work that needs it. Reading a title or following a link is not that result.

The same destination can serve either purpose. Ordinary wording should make the difference clear; short Source: and Apply: labels can help in compact lists but are not required. A contents entry or plain catalogue locator is only navigation. If a substantive reference is ambiguous, use FPF E.11.PUA:4.1.1 to decide what to read or apply. When writing such a passage, use FPF E.8:4.2.2.2 to make its purpose clear without redundant labels. An extract retains any necessary purpose or condition that would otherwise be lost with its heading or introduction.